Instructions

• Place 1cupsalted butter, diced into cubes, in a medium saucepan and heat over medium. Swirl occasionally and cook until the butter is browned (it will melt, splatter, foam, then golden bubbles and brown specks will appear). Remove from heat and immediately pour the browned butter into a heatproof bowl, scraping the pan with a rubber spatula to transfer the browned bits. Let the butter cool until just warm to the touch, about 20–25 minutes.
• While the butter cools, preheat the oven to 350°F (175°C). Line baking sheets with a Silpat or parchment paper, or lightly grease them.
• In a medium bowl, whisk together 2 1/4cupsall-purpose flour, 2tspcornstarch, 1tspbaking powder, 1/4tspbaking soda, and 1/4tspsalt. Set the dry mixture aside.
• In the bowl of an electric stand mixer fitted with the paddle attachment (or using a large bowl and a hand mixer), add the cooled browned butter, 1/2cupgranulated sugar, and 1/2cuppacked light-brown sugar. Mix on medium speed until well blended.
• Add 1large egg, 1large egg yolk, and 2tspvanilla extract to the butter-sugar mixture and mix until combined.
• With the mixer on low speed, slowly add the dry ingredients to the wet ingredients and mix just until combined. Do not overmix.
• Scoop dough in 1 1/2 Tbsp portions, roll each portion into a ball, and place them on a prepared baking sheet, spacing about 2 inches apart. Pour 1/4cupgranulated sugar (for rolling cookies) into a small bowl and roll each dough ball in the sugar to evenly coat. After coating, place each ball back on the baking sheet and gently flatten each to about 1/2 inch thick using the bottom of a flat measuring cup or drinking glass.
• Bake the cookies in the preheated oven for 9–11 minutes, until the edges are set and the tops show slight cracks. Remove from the oven and let the cookies cool on the baking sheet for several minutes.
• Transfer the cookies to a wire rack and let them cool completely before frosting.
• To make the Salted Caramel Frosting: in a large mixing bowl, use an electric hand mixer on low speed to beat 1/4cup+ 2 Tbsp caramel sauce, 1/4cupbutter (softened), 1/2tspvanilla extract, and 1/2tsp of the 3/4tspscoarse sea salt (reserve the remaining 1/4 tsp) until pale and smooth, about 1 minute. Add 2cupspowdered sugar and mix on low speed until well blended and smooth. If needed, scrape down the bowl and mix briefly again.
• Spread or pipe the frosting onto the completely cooled cookies. Immediately sprinkle the frosted cookies with the remaining 1/4 tsp coarse sea salt so the salt adheres before the frosting sets. Store the finished cookies in a single layer in an airtight container.